Effects of external phase on D-cycloserine loaded W/O nanocapsules prepared by the interfacial polymerization method

In vitro and in vivo evaluation of 10-hydroxycamptothecin-loaded poly (n-butyl cyanoacrylate) nanoparticles prepared by miniemulsion polymerization

In this paper, 10-hydroxycamptothecin (HCPT)-loaded poly (n-butyl cyanoacrylate) nanoparticles (HCPT-PBCA-NPs) co-modified with polysorbate 80, soybean phospholipids, and polyethylene glycol (100) monostearate were successfully prepared via miniemulsion polymerization, and were characterized for particle size, morphology, zeta potential, encapsulation efficiency (EE) and drug loading capacity (DL). The chemical structure of HCPT-PBCA-NPs and the state of HCPT in the PBCA-NPs were investigated by DSC, FTIR and ¹H NMR. Additionally, drug release, cytotoxicity, cellular uptake capacity, cellular uptake mechanism, and in vivo behavior of NPs were investigated as well. The particles were 92.7nm in size with a high EE of 94.24%. FTIR, ¹H NMR, and DSC demonstrated complete polymerization of BCA monomers and the drug was in a molecular or amorphous form inside the NPs. In vitro release of the drug from HCPT-PBCA-NPs exhibited sustained-release and less than 60% of HCPT was released from the NPs within 24h of dialysis. Cellular uptake study displayed that Caco-2 cell uptake of NPs was governed by active endocytosis, clathrin- and caveolin-mediated process, and increased with the increase of the NPs concentration and the time. The pharmacokinetic study in rats showed that encapsulation of HCPT into PBCA-NPs increased the C_max and AUC_0-t about 6.52 and 7.56 times, respectively, in comparison with the HCPT suspension. It was concluded that HCPT loaded PBCA-NPs prepared by miniemulsion polymerization could be promising in oral drug delivery.

Design, characterization and in vitro evaluation of novel shell crosslinked poly(butylene adipate)-co-N-succinyl chitosan nanogels containing loteprednol etabonate: A new system for therapeutic effect enhancement via controlled drug delivery

This study reports on the development of a novel mucoadhesive and biocompatible shell-crosslinked nanogel system based on poly(butylene adipate) (PBA) and N-succinyl chitosan (S-Cs) by coupling reaction with a new formulation method. For this purpose, two different molecular weights of dendrimerized PBA with amine terminated functional groups were synthesized separately and characterized well by FT-IR, (1)HNMR and GPC. The PBA nanoparticles containing loteprednol etabonate (LPE) prepared by O/W emulsion technique were reacted immediately with modified carboxylated chitosan via carbodiimide chemistry. TEM photographs of the nanoparticles and crosslinked nanoparticles displayed a spherical morphology closely corresponding to the results obtained by DLS. On The other hand, biodegradability, biocompatibility and bioadhesiveness of the prepared nanoparticles were also studied. It is concluded that the core-shell structured nanogels can be used as novel ocular drug delivery systems with appropriate loading capacity for slightly water soluble LPE as an anti-inflammatory drug.

Initial characterization of D-cycloserine for future formulation development for anxiety disorders

The purpose of this study is to characterize D-cycloserine (DCS) physicochemical properties to facilitate future formulation development of DCS for anxiety disorders. A stability-indicating HPLC assay method for the quantitation of DCS was developed and calibrated to be used for this study. The partition coefficient was determined and compared with the predicted value. The solution stability of DCS was studied under various pH (2.0-11.5) and ionic strengths of 10 and 20 mM at physiological temperature of 37°C. The 250 mg capsule was compounded to the nominal strength of 50 mg used for anxiety disorders. These capsules were then put under stability. The in vitro dissolution was also carried out at 37°C as per the United States Pharmacopeia (USP) guidelines. The partition coefficient value (Kp) determined for the DCS was log Kp = -2.89 ± 0.06 (n = 6). The pH-solution stability profile shows that DCS has maximum stability under alkaline conditions. The maximum rate of degradation was seen at pH of 4.7. The mean percent recovery of DCS from the capsules compounded to strength of 50 mg was 100.3 ± 1.4. The stability study of the reformulated capsules concluded that reformulated DCS is stable for at least one year at room temperature. The in vitro dissolution illustrates that all the DCS is released from the capsules in 10 min. The present characterization of DCS study will serve as guidance for the future directions regarding the reformulation of DCS in order to be used in anxiety disorders.

Preparation of chondroitin sulfate nanocapsules for use as carries by the interfacial polymerization method

In this paper, the method of interfacial polymerization in emulsion was employed to fabricate chondroitin sulfate-methacrylate (ChSMA) nanocapsules, in which poor water-soluble drug of indomethacin (IND) could be effectively encapsulated. The morphology and the size distribution of synthesized nanocapsules were characterized by field emission scanning electron microscopy (FESEM) and dynamic light scattering (DLS) techniques. The quantitative drug loading was investigated. The IND/ChSMA noodle-like self-assemblies were observed with the increase of IND feed concentration, and the interactions between IND and ChSMA were illuminated by FT-IR and XRD measurements. The in vitro drug release of IND-loaded nanocapsules and IND/ChSMA self-assemblies were also carried out in simulated body fluid pH 7.4 at 37°C.